1. Field of the Invention
The present invention relates generally to electrical circuits, and more particularly but not exclusively to soft-burst circuits for switched-mode power supplies.
2. Description of the Background Art
A power supply is an electrical circuit that receives an input voltage to deliver a regulated output voltage to a load. In a switched-mode power supply, switching of a single transistor or a pair of synchronously switched transistors is controlled to maintain the output voltage to within a desired output voltage range. One problem with switched-mode power supplies is that undesirable audible noise may occur when varying the switching frequency of the output transistors. The audible noise is especially problematic in high-efficiency power supplies that use pulse-skipping techniques to turn off the output transistors at light load levels.